This laboratory has been developing transgenic technology to visualize gene expression as it is occurring in zebrafish embryos and larvae. The investigators have made germ-line green fluorescent protein expressing transgenic zebrafish using both DNA microinjection and pseudotyped retroviral vector infection techniques. In this component, they plan to use this technology to visualize the effects of mutations upon the development of the embryonic neural tube and to try to identify and isolate genes involved in neural tube development. Any new genes would then be characterized and used as potential genes that might play roles during mammalian neural tube development, allowing the investigators to combine efforts with others= efforts in this program project grant. The means by which the investigators plan to do this include: (1) the characterization of the fluorescent expression patterns of different transgenic zebrafish which have been shown to express green fluorescent protein (or mutant versions thereof) in different and overlapping regions of the nervous system and to possibly modify the transgenes for more efficient use in examining the nervous system; (2) the crossing of these transgenic lines with a series of mutants in the bmp signaling pathway so that specific effects upon sub-components of the neural tube could be visualized and computer archived as they are happening; and (3) the use of a new promoter trap retroviral vector that this laboratory has constructed to identify and isolate genes expressed during neural tube development so that their expression could be characterized in zebrafish and possibly used to explore what roles they might play in mammalian neural tube development by other members of this program project.